I am mounting a BME 44 on the GP Extra 300 ARF. I think you will have to cut out the bottom of the cowl with the 44 or 50. I would go with the 50 for power. I will be mounting my engine in the next few days so I will let you know. Remember you need to cut some holes in the cowl for cooling. You have the two air scoops on the front, but you need exit holes for the air. The exit holes will be on the bottom. I can tell you that you will have to cut out holes for the exhaust.

Chris

Chris